12strings

Ok, so in order for me to achieve the "front of knee directly over axel of pedal when pedals are horizontal" I have to set the saddle as far back as I can possibly put it...which i'm sure puts more strain on the saddle rails.

1. Does this mean my bike is simply to small?

2. OR...does this mean my bike's seat tube is simply angled more steeply for a more aggressive position, and I should not worry about trying keep my knees over my pedals?

RR3

Could be either #1 or #2 . Could be both. If your saddle is too low, you might not be able to get the right setback. With a 72-74 degree seat tube angle, the saddle will go back some as you move it up and it will go forward when you move it down. Trig....tangents, etc. This might be the issue or you could have proportionally long femurs like I do. My saddle is always slammed.

Whether to worry depends on your comfort. Is the bike comfortable? Is it balanced. I personally think the saddle position should be set to balance your torso so that the right amount of pressure is on your hands, arms, and shoulders and that the bike handles in a neutral way. Knee over pedal is all BS.

Blue Belly

my guess, saddle too low or bike too small. Provide more info...?

12strings

I've adjusted my saddle height up And down, but I'm pretty sure it's in the ballpark...any movement that would dramatically affect forward back position would definitely be too high/low....

I was having trouble feeling pitched forward with too much weight on my hands, so once I finally started moving the saddle back, it helped a lot since I was now in a more seated position instead of a leaning forward position...I'm just wondering if I've gone too far...I don't know my bikes dimensions...I assume it is a generic"medium"...I am 5'9".

Blue Belly

Measure the frame. 5'9" should be in the medium range. 55cm? My wife is 5'9" & 54cm is a bit small. Depends on proportions though.

12strings

My bike has a perfectly horizontal top tube.

Actual top tube length, from center of seat post to center of stearing tube = 57cm

Measuring about 2 inches up (from the bottom of my stem...it is on top of all the spacers)...it is 58cm. (this because the seat tube angles more steeply than the steering tube).

Upon doing some math and holding up a protractor to my bike, I believe the seat tube angle is about 74 degrees, which I just looked up is pretty steep...that would explain a lot of the issues I've been having feeling like I am too far forward.

Still not sure about my bike size...but I do know that for me, I would like the handlebars to be about level with the seat...and right now they are significantly lower.

ThermionicScott 

I would get those bars up if that's what you want. Perhaps you are pushing backward too much because of the low bars, and that's why it seems like you can't get the saddle back far enough. Just a thought...

AnthonyG

Yes, a seat tube angle of 74 degrees is too steep for the vast majority of the population. I'm not sure if it would fit ANYBODY but I can't rule it out.

Try a seatpost with 40 to 50mm of setback on the clamps. Most standard seatposts have 25mm of setback at the clamps. This will allow the seat to be clamped closer to the middle of the seat rails.

Anthony

headset

Race bike geometry vs touring geometry. A steeper seat tube puts the rider further forward over the cranks and more weight on the front wheel. This results in a better 'jump' capacity (quickly rising out of the saddle to accelerate) and better handling at speed. Touring geometry places the hips further back relative to the bb, taking pressure off the hands and promoting a more upright position. From about 1975 to present a 74 degree seat tube angle was fairly standard for a race bike, touring bikes tend to be in the 72-73 degree range.

Nothing wrong with having a saddle pushed back if that's what your body needs for a given frame geometry.

Doc V

Try fitting using Peter White's guide, which can be found here How to Fit a Bicycle. I find it more helpful to fit a frame by its top tube rather than its seat tube that way if you have disproportionately longer legs you don't buy a frame that is too large. It could be you need a setback seat post, but first you should make sure the seat height and fore-aft are set properly.

Drew Eckhardt 

It could be your seat tube is too steep for a 0 offset seat post.

25mm offset posts are common, a bit more available if you look like the FSA K-Force SB32 and Ambrosio Momentum at 45mm (27.2 only).

It could be a saddle with very short rails like Brooks.

We need more parts details.

springs

Could you say more about this, or define what you mean by "vast"?

12strings

I put some further measurements in a reply above...only real thing to add is that I have a long skinny saddle...

It seems from other threads that a 57cm.top tube is a bit long for my 5'9". Height....agree Or not?

AnthonyG

That's a BIG question. To answer it I guess you have start with asking the question, What is the seat tube ANGLE doing in the first place?

Without going right into it as I don't have the time right now, the seat tube angle is positioning your body's centre of gravity in relation to the bottom bracket, and/or, positioning your legs in relation to KOPS (knee over pedal spindle).


So more questions. Does a seat tube angle of 74 degrees place ANYONE at KOPS? No. Not that I know of. Not unless their cranks are too long. At 74 degrees I expect riders to be in front of KOPS. Being in front of KOPS works for time trial bikes or MAYBE criterium bikes but not so great for long stage races.

Where does 74 degrees balance a riders weight? Forward on their arms and shoulders is the answer. Lots of weight on hands and shoulders is not what recreational riders want.

I'm not claiming that KOPS is a hard and fast rule that must be obeyed but it seems t work as a decent balance in a range of situations. Being in front of KOPS is useful for time trial bikes with time trial bars. Being behind KOPS is more relaxing for recreational riders.

74 degree seat tube angles only work in a handful of situations. Why its considered a standard is beyond me.

More involved but that's a start.

Anthony

Road Fan

You need your saddle set farther back from the BB. KOPS is kind of an arbitrary guideline, nobody seems really sure what it offers. The real criterion IMHO is to move your center of gravity back so that the pressure on your hands feels comfortable. This would be true for you regardless of frame size.

KOPS gets you close to a balance point (your center of gravity over the BB). Personally I like to be about 2 cm behind KOPS, but I have extra upper body weight (self-contained long-distance fuel supply!).

Several ways to move the saddle back (aka increase the setback):

1. slide it back on its rails with no parts changes
2. get a saddle with longer rails and then slide it back
3. get a seatpost with more setback and possibly longer rails and then slide it back
4. get a different frame with a numerically lower seat tube angle.

With a lower seat tube angle, you get about 1 cm setback with each degree lower seat tube angle. Before you go down this road try options 1 through 3 to see how much added setback you need. If you wanted to have a frame built, most builders seem to think it's odd to ask for something less than 72.5, in my experience.

Increasing the setback increases the practical top tube length (measuring from the saddle center to the center of the hoods, for example), so now just selecting a frame based on TT length or effective TT length is not enough. A good TT length on a bike with proper saddle placement could be way too long on a bike with a numerically higher seat tube angle, after you adjust saddle setback to achieve your balance. The reach to the bars could then be longer than is comfortable.

12strings

Thanks for all the insight.

1. I will not be getting a new bike any time soon. (a) no money for that. (b) I want to get this bike dialed in as best i can so i actually know more about what to look for in my next bike. So it's cheap and free solutions for now.

2. here's really grainy internet image of my model bike with a picture of a protractor super-imposed over it. seat tube might be anywhere from 72-72...I can't really tell. As I said, all i do know is that if I have my seat anywhere near centered on the rails, my knees are well forward of kops...AND, i often feel like I am falling forward, using my arms to holdmyself up.



I have my seat almost as far back as I

headset

This is a terrific summary!

FWIW -When my CG is far enough behind the BB to achieve a balanced position, I'm comfortable with a significantly longer reach than if I'm too forward on the bike. Seems counterintuitive, moving your saddle back to take pressure off your hands, but it works.

12strings

oops, pic...

cale

Tape a plumb line to your knee, move the bike to where you can sit comfortably and not fall over, backpedal til the drive-side* crank is in the 3'oclock position, look at location of plumb line in relation to the pedal. Don't get too carried away with what being in front or behind the pedal means, just try to get comfortable.

It is best to try the above when wearing your cleats, if applicable. It may be beneficial to loosen, or remove, the cleat so that your leg can be in a relaxed and natural position when you check your position.

* I would check the side of your dominant leg.